1. Field of the Invention
The invention relates to a device for attaching a member in replacement of part of a set of teeth, comprising: a hollow pin to be implanted in jawbone and a coupling pin to be rigidly attached to the implantation pin by means of a ball-and-socket joint.
2. Descripton of the Prior Art
Such a device is disclosed in the European Patent Application 0,263,274. It is designed for anchoring in the mouth of, for instance, a human being, a dental-replacement member such as a crown, bridge or prosthesis in replacement of one or more teeth and/or molars.
A dental-replacement member is applied by first implanting one or more hollow pins in the patient's jawbone. After a certain time, the coupling pin for coupling the dental-replacement member is attached thereto. The exact position where such an implantation pin is implanted, as well as the orientation of the implantation pin relative to the bone, mainly depends on the constitution of the bone in question: it will be clear that it is desirable for the implantation pin to be implanted in a bone portion that satisfies certain minimum requirements with respect to thickness and solidity. It may thus happen that the orientation of the implantation pin relative to the bone deviates from the desired orientation relative to the dental-replacement member.
Particularly when a plurality of implantation pins are used to attach one and the same dental-replacement member, it is desirable for the coupling pins of these implantation pins to be oriented parallel to each other. However, in practice it is almost impossible to attach the implantation pins in parallel orientation: some degree of non-parallellism is nearly always inevitable.
Therefore, in order to facilitate the placing of the dental-replacement member onto the pins, and/or to allow for the setting of the orientation of the dental-replacement member with respect to the implantation pin, the coupling pin is attached to the implantation pin by means of a ball-socket joint. When orienting the coupling pin with respect to the implantation pin, the ball-socket joint is loosened; when the desired orientation is achieved, the ball-socket joint is secured.
In the known device, the ball-socket joint is an ordinary ball-socket joint which in itself provides only the orientation facility but not the fixation, while the above-mentioned securing of the ball-socket joint is achieved by the provision of securing means in the form of a clamping screw. Consequently, it is necessary to provide for some passage so that a tool can reach the clamping screw. Further, in the known device the socket of the ball-socket joint is necessarily made in two-part form, the two parts being screwed together. In order to let the socket receive the ball, said two socket parts need to be screwed loose, and after placing the ball in one socket part, the other socket part, which is shaped as a housing, must be placed over the ball and screwed to the first socket part.
One disadvantage of this known device is that it is constructionally complicated, in that it comprises two screw connections: one screw connection for the socket housing to the other socket part, and another screw connection for the securing screw.